# Recent content by classy cal

1. ### A Gamma matrices

Thank you Peter. I see now that the order of any two adjacent matrices can be swapped and the sign changed. It is "easy to show". I appreciate you taking the time to point me in the right direction.
2. ### A Gamma matrices

"It is easily shown" that the gamma 5 matrix anticommutes with the four gamma matrices. Can someone tell me how or provide a link to such proof?
3. ### A Press Schechter function -- the variance on mass scale

In obtaining the Press Schechter function, the variance on mass scale is differentiated with respect to mass. The variance on a mass scale is a function of wavenumber k through the Power spectrum and transfer function. To eliminate k dependence, some value of k must be inserted into the...
4. ### Sakurai Modern Quantum Mechanics (Second Edition) Eq. 1.7.15

Thank you for your reply, it has helped me understand manipulation of bra-kets.
5. ### Sakurai Modern Quantum Mechanics (Second Edition) Eq. 1.7.15

Homework Statement Reading Sakurai I cannot see how he gets to the end of 1.7.15 as below: Homework Equations ∫dx'|x'><x'-dx' |α> = ∫dx'|x'>{<x' |α>-Δx'∂/∂x'<x' |α>} The Attempt at a Solution I tried a Taylor expansion but cannot see how this is derived.
6. ### Lorrain & Corson

Many thanks Redbelly.
7. ### Lorrain & Corson

can someone help me with a derivation in L&C. I am wrestling with Figure 18.9 (Fig 7.20 in second edition) . In Equations 18.36 and 18.37 (7.99 and 7.100), the element dl is substituted with acos(phi)dphi and I cannot see how this is derived.